The development of collagen-urethane extension catheters has been successfully completed in that an extension added to a conventional catheter can be advanced through the acute curves of the carotid siphon to reach well into the branches of the middle cerebral avoiding the ophthalmic branch. This procedure allows therapeutic agents to be delivered to the branches that supply tumors (glioblastoma) on the basis that this would avoid the destruction of the eye and concentrate the therapeutic action on the tumor. Clinical application of the technique seems to indicate that the therapeutic agent forms a stream in the vessels that diverts the agent from the tumor to cause destruction of remaining normal brain. These procedures have been suspended pending results of methods to correct the streaming problems. The collagen extension catheter does permit rapid access and does not swell to occlude the carotid when pressurized. Cook catheters will take over the construction and make the catheter available as required. The demonstration of the technique of making high strength collagen tubes for production of vascular prosthesis in the 3 mm range will not be persued.